A Royal Enfield forum for the people

[Tim]

This topic is popping on the other board so I figured I would cross post.

There are 2 generations of sprag clutch for the Royal Enfield, as with all things that are improved you should always go with the latest and greatest option available. As of this moment there is only one place you can buy the newest version on the open market, so naturally Western Cycle Supply will be offering them soon.

Please note all of the listings I see on eBay are for the older inferior version. The 2nd generation should have springs on either side of all the teeth (I think they are called teeth).

I would love to publish a knowledge base article on this topic. If anyone is well versed on why the 1 gens fail and why the 2nd gen is an improvement. By all means please put it in writing and submit the article.

[gashousegorilla]

The way in which the 1st generation sprag bearing held the individual sprags in place , was with metal tabs on top of them, in a caged assembly. So if there was a kick back... or anytime the crankshaft were to be rotated back words... counterclockwise from the right side of the motor. The individual sprags would push out and away from center and bend these retaining metal tabs out. This bending out of the metal tabs would loosen the individual sprags in the cage that they are housed in, rendering the sprag bearing useless. And depending on how often or how hard the counter clockwise rotation happened, would determine how long the sprag would last... But NOT very long !! It was crap ! Once the tabs were bent out, it was done for. When taking the gear assembly out and separating it... most would find the sprags falling out of their cage.

A kick back can happen from... a miss fire when one goes to kick start the motor, if the battery is weak or there is a charging issue , if the motor has an ignition problem or in a poor state of tune, or if the bike gets stalled out on the road in a whoops! moment in first gear and etc and etc... Anything that causes the bike to be difficult to start or is suddenly stalled out.

The way in which the second generation sprag bearing holds the individual sprag in place , is with a spring instead of those metal tabs. So in the event of a kick back.... and it DOES happen !... the spring will allow the sprags to move out a little during a kick back, and move them back in place. It 's much better design. I have only seen a couple/few go bad in the 8 year's or so since they came out. Generally when and if they go bad, the sping that retains the individual sprags in place becomes weak. In which case one would need to either buy and replace the sprag bearing, OR a more practical and inexpensive repair would be to just replace the spring.... if it is available .

The 1st generation sprag bearing will only fit into the 1st generation gear assembly. And the 2nd generation sprag bearing will only fit into the 2nd generation gear assembly.... they are not interchangeable. I believe the second generation sprag came out in around 2011 ? So if you have an old UCE that has the 1st generation sprag/gear, and your sprag bearing goes bad, you must buy the whole 2nd generation sprag/gear assembly.

[Tim]

Thanks GHG, I put it on paper. check it out.

kb/viewarticle?a=4

[swamp2]

That was an informational read, thanks for posting it. FWIW, I recently purchased a sprag clutch that was advertised as a genuine RE spare and packaged as such. I haven't put it in my '09 G5 yet, but did look at the assembly and it most definitely of the 2nd generation design. Probably put it in next week, getting the bike running was the first priority.

Steve

[gashousegorilla]

That was an informational read, thanks for posting it. FWIW, I recently purchased a sprag clutch that was advertised as a genuine RE spare and packaged as such. I haven't put it in my '09 G5 yet, but did look at the assembly and it most definitely of the 2nd generation design. Probably put it in next week, getting the bike running was the first priority.

Steve

No problem Steve. I can tell you that we have really ... REALLY , put that 2nd generation sprag to the test over the years. I'm talking high compression piston and combustion chamber's.... short stock duration cams with HIGH cylinder pressures. Long duration cams with not quite so as high a cylinder pressure ? Doubled the horse power of the bike... tuned the bike from scratch with hard initial start up's until it was tuned, experimentation and etc and etc. and etc. And it has been GOOD, and really taking a beating. On two different bikes now that I think of it ?! You may hear from guys that the Auto De-comp installed on the stock exhaust cam in there to help protect the Sprag from kick back. THAT... In my personal experience over the the years is a bunch of horse shyte ! That First gen would fail , because it was a Shyte sprag. And the only thing that auto decomp is there for , is to make it so the bike can be a little more easily kick started. WHEN and IF it works.

When you put that new sprag on... Use red loctite on that bolt that mounts the sprag gear to the shaft. And torque it down to 48 ft lbs. That sucker has to be TIGHT and stay in there. It is a regular right hand thread and the shaft rotates counter clockwise on that side of the motor. So the bolt will want to loosen up if it ain't tight enough... And you certainly do not want that bolt dropping out on you into that primary drive. On a C-5 style left side cover ... the bolt can loosen and drop. On a G-5 style left side cover, if the bolt loosens, it will back out and the head of the bolt will hit the inside of the cover and stay there. But either way, it's VERY important to make sure that bolt is tight and to check it periodically .

[swamp2]

Thanks much for the installation advice, I shall follow it to the letter. A quick question, when reinstalling the side cover, is use of some gasket maker (e.g. ultra black, hylomar, etc) recommended or is it not needed?

[gashousegorilla]

Thanks much for the installation advice, I shall follow it to the letter. A quick question, when reinstalling the side cover, is use of some gasket maker (e.g. ultra black, hylomar, etc) recommended or is it not needed?

Yes . You can use Permatex Ultra Grey or Black ... any of the goop that resists oil. They DO make a left side cover gasket for the motor. But the goop works fine on the left side. NO goop on the right side cover if you ever take it off, because there is an oil passage there that should not be blocked.

With the bike on the center stand and up right, you will get very little oil coming out under that left side cover BTW.... a drip pan should do ya.

[Tim]

Thanks much for the installation advice, I shall follow it to the letter. A quick question, when reinstalling the side cover, is use of some gasket maker (e.g. ultra black, hylomar, etc) recommended or is it not needed?

They DO make a left side cover gasket for the motor. But the goop works fine on the left side.

@GHG I was trying to remember if they eliminated the gasket because of some type of clearance issue, but my black book tells me nothing. Which leaves us with, it was eliminated to save money?? If it's worth anything I never came across anyone that insisted on having the gasket.

@Steve note below the official sealant is Loctite 5699. However GHG is correct, anything will do, the important thing is don't use too much.

[gashousegorilla]

Cheap cost saving thing I think ? They ARE out there and I use them... and have one or two here . Although my 09 bike did not have one originally. I like a gasket instead of the goop. Less chance of an errant piece of goop getting into an oil passage I think. BTW... that sprag bolt will still drop out on a C-5 style cover even without a gasket and when a liquid type gasket is used....

[swamp2]

It was a sunny day in the 50's today, very weird for upstate NY in December. Anyway, not wanting to pass up the opportunity, I went out an romped around on the '09 G5 for a while, then changed the oil and the sprag clutch. Mine had the 1st generation version in there - was still working fine (6700 miles). But I'd been made paranoid about the destruction stories on the thing, and as it was the main issue brought up as advising against buying an early UCE on CMW, I just wanted to change it and get it off my mind.

Even though the clutch didn't need repair right now, I was glad I did it. I found the 17mm bolt on the sprocket had backed out completely - held in place by the case cover I guess. The 24mm nut was so loose I could back it off without a ratchet on the socket. Scary. Per GHG's guidance, I applied red locktite liberally and torqued them both down.

There was a gasket on it, but it got pretty trashed in removal, so I put it back together with some Ultra Black without the gasket.

Switching gears for a moment - the first oil change I'd done on my C5 last week, the filter was stamped with a Purolator #. Today's (from the same ebay order) was marked differently - something like efolic? Looked fine though.